The packet over optical network scenario is one that is becoming more common in the current communication panorama. Traditionally, the performances at the two layers are measured using the following parameters:
Packet Layer. The Packet Error Rate (PER) is the number of incorrectly received data packets divided by the total number of received packets during a studied time interval.
Optical Layer. The Bit Error Rate (BER) is the number of bit errors divided by the total number of transferred bits during a studied time interval.
There are many known ways of measuring these and many ways of managing the different layers to remedy the situation if the error rate is not acceptable.